{-# LANGUAGE DataKinds #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeOperators #-}

module Cachix.Client.Commands
  ( authtoken,
    create,
    generateKeypair,
    push,
    use,
  )
where

import qualified Cachix.API as API
import Cachix.API.Error
import Cachix.Client.Config
  ( BinaryCacheConfig (BinaryCacheConfig),
    Config (..),
    mkConfig,
    writeConfig,
  )
import qualified Cachix.Client.Config as Config
import Cachix.Client.Env (Env (..))
import Cachix.Client.Exception (CachixException (..))
import Cachix.Client.HumanSize (humanSize)
import qualified Cachix.Client.InstallationMode as InstallationMode
import qualified Cachix.Client.NixConf as NixConf
import Cachix.Client.NixVersion (assertNixVersion)
import Cachix.Client.OptionsParser
  ( CachixOptions (..),
    PushArguments (..),
    PushOptions (..),
  )
import Cachix.Client.Push
import Cachix.Client.Secrets
  ( SigningKey (SigningKey),
    exportSigningKey,
  )
import Cachix.Client.Servant
import Cachix.Client.Store (Store)
import qualified Cachix.Types.SigningKeyCreate as SigningKeyCreate
import Control.Exception.Safe (handle, throwM)
import Control.Retry (RetryStatus (rsIterNumber))
import Crypto.Sign.Ed25519
import qualified Data.ByteString.Base64 as B64
import Data.List (isSuffixOf)
import Data.String.Here
import qualified Data.Text as T
import Network.HTTP.Types (status401, status404)
import Protolude
import Servant.API (NoContent)
import Servant.Auth.Client
import Servant.Client.Streaming
import Servant.Conduit ()
import System.Directory (doesFileExist)
import System.FSNotify
import System.IO (hIsTerminalDevice)

authtoken :: Env -> Text -> IO ()
authtoken env token = do
  -- TODO: check that token actually authenticates!
  writeConfig (configPath (cachixoptions env)) $ case config env of
    Just cfg -> Config.setAuthToken cfg $ Token (toS token)
    Nothing -> mkConfig token

create :: Env -> Text -> IO ()
create _ _ =
  throwIO $ DeprecatedCommand "Create command has been deprecated. Please visit https://app.cachix.org to create a binary cache."

generateKeypair :: Env -> Text -> IO ()
generateKeypair env name = do
  cachixAuthToken <- Config.getAuthTokenRequired (config env)
  (PublicKey pk, sk) <- createKeypair
  let signingKey = exportSigningKey $ SigningKey sk
      signingKeyCreate = SigningKeyCreate.SigningKeyCreate (toS $ B64.encode pk)
      bcc = BinaryCacheConfig name signingKey
  -- we first validate if key can be added to the binary cache
  (_ :: NoContent) <-
    escalate <=< (`runClientM` clientenv env) $
      API.createKey cachixClient cachixAuthToken name signingKeyCreate
  -- if key was successfully added, write it to the config
  -- TODO: warn if binary cache with the same key already exists
  let cfg = case config env of
        Just it -> it
        Nothing -> Config.mkConfig $ toS $ getToken cachixAuthToken
  writeConfig (configPath (cachixoptions env)) $
    cfg {binaryCaches = binaryCaches cfg <> [bcc]}
  putStrLn
    ( [iTrim|
Secret signing key has been saved in the file above. To populate
your binary cache:

    $ nix-build | cachix push ${name}

Or if you'd like to use the signing key on another machine or CI:

    $ export CACHIX_SIGNING_KEY=${signingKey}
    $ nix-build | cachix push ${name}

To instruct Nix to use the binary cache:

    $ cachix use ${name}

IMPORTANT: Make sure to make a backup for the signing key above, as you have the only copy.
  |] ::
        Text
    )

notAuthenticatedBinaryCache :: Text -> CachixException
notAuthenticatedBinaryCache name =
  AccessDeniedBinaryCache $
    "Binary cache " <> name <> " doesn't exist or it's private. " <> Config.noAuthTokenError

accessDeniedBinaryCache :: Text -> CachixException
accessDeniedBinaryCache name =
  AccessDeniedBinaryCache $ "Binary cache " <> name <> " doesn't exist or it's private and you don't have access it"

use :: Env -> Text -> InstallationMode.UseOptions -> IO ()
use env name useOptions = do
  cachixAuthToken <- Config.getAuthTokenOptional (config env)
  -- 1. get cache public key
  res <- (`runClientM` clientenv env) $ API.getCache cachixClient cachixAuthToken name
  case res of
    Left err
      | isErr err status401 && isJust (config env) -> throwM $ accessDeniedBinaryCache name
      | isErr err status401 -> throwM $ notAuthenticatedBinaryCache name
      | isErr err status404 -> throwM $ BinaryCacheNotFound $ "Binary cache" <> name <> " does not exist."
      | otherwise -> throwM err
    Right binaryCache -> do
      () <- escalateAs UnsupportedNixVersion =<< assertNixVersion
      user <- InstallationMode.getUser
      nc <- NixConf.read NixConf.Global
      isTrusted <- InstallationMode.isTrustedUser $ NixConf.readLines (catMaybes [nc]) NixConf.isTrustedUsers
      isNixOS <- doesFileExist "/etc/NIXOS"
      let nixEnv =
            InstallationMode.NixEnv
              { InstallationMode.isRoot = user == "root",
                InstallationMode.isTrusted = isTrusted,
                InstallationMode.isNixOS = isNixOS
              }
      InstallationMode.addBinaryCache (config env) binaryCache useOptions $
        InstallationMode.getInstallationMode nixEnv useOptions

-- TODO: lots of room for performance improvements
push :: Env -> PushArguments -> IO ()
push env (PushPaths opts name cliPaths) = do
  hasStdin <- not <$> hIsTerminalDevice stdin
  inputStorePaths <-
    case (hasStdin, cliPaths) of
      (False, []) -> throwIO $ NoInput "You need to specify store paths either as stdin or as an command argument"
      (True, []) -> T.words <$> getContents
      -- If we get both stdin and cli args, prefer cli args.
      -- This avoids hangs in cases where stdin is non-interactive but unused by caller
      -- some programming environments always create a (non-interactive) stdin
      -- that may or may not be written to by the caller.
      -- This is somewhat like the behavior of `cat` for example.
      (_, paths) -> return paths
  cacheSecret <- findPushSecret (config env) name
  store <- wait (storeAsync env)
  void $
    pushClosure
      (mapConcurrentlyBounded (numJobs opts))
      (clientenv env)
      store
      PushCache
        { pushCacheName = name,
          pushCacheSecret = cacheSecret
        }
      (pushStrategy env opts name)
      inputStorePaths
  putText "All done."
push env (PushWatchStore opts name) = withManager $ \mgr -> do
  store <- wait (storeAsync env)
  pushSecret <- findPushSecret (config env) name
  _ <- watchDir mgr "/nix/store" filterF (action store pushSecret)
  putText "Watching /nix/store for new paths ..."
  forever $ threadDelay (1000 * 1000)
  where
    action :: Store -> PushSecret -> Action
    action store pushSecret (Removed fp _ _) =
      let storePath = toS $ dropEnd 5 fp
       in Control.Exception.Safe.handle (logErr fp) $ void $
            pushClosure
              (mapConcurrentlyBounded (numJobs opts))
              (clientenv env)
              store
              ( PushCache
                  { pushCacheName = name,
                    pushCacheSecret = pushSecret
                  }
              )
              (pushStrategy env opts name)
              [storePath]
    action _ _ _ = return ()
    logErr :: FilePath -> SomeException -> IO ()
    logErr fp e = hPutStrLn stderr $ "Exception occured while pushing " <> fp <> ": " <> show e
    filterF :: ActionPredicate
    filterF (Removed fp _ _)
      | ".lock" `isSuffixOf` fp = True
    filterF _ = False
    dropEnd :: Int -> [a] -> [a]
    dropEnd index xs = take (length xs - index) xs

retryText :: RetryStatus -> Text
retryText retrystatus =
  if rsIterNumber retrystatus == 0
    then ""
    else "(retry #" <> show (rsIterNumber retrystatus) <> ") "

pushStrategy :: Env -> PushOptions -> Text -> Text -> PushStrategy IO ()
pushStrategy env opts name storePath =
  PushStrategy
    { onAlreadyPresent = pass,
      on401 =
        if isJust (config env)
          then throwM $ accessDeniedBinaryCache name
          else throwM $ notAuthenticatedBinaryCache name,
      onError = throwM,
      onAttempt = \retrystatus size ->
        -- we append newline instead of putStrLn due to https://github.com/haskell/text/issues/242
        putStr $ retryText retrystatus <> "compressing and pushing " <> storePath <> " (" <> humanSize (fromIntegral size) <> ")\n",
      onDone = pass,
      withXzipCompressor = defaultWithXzipCompressorWithLevel (compressionLevel opts),
      Cachix.Client.Push.omitDeriver = Cachix.Client.OptionsParser.omitDeriver opts
    }